Field of the Invention
The present invention relates to a direct fuel injection internal combustion engine having an injector for directly injecting fuel into a combustion chamber thereof, and particularly to the internal combustion engine which is configured so that a tumble flow is generated in the combustion chamber.
Description of the Related Art
Japanese Patent Laid-open Publication No. 2014-77421 (JP'421) discloses a direct fuel injection internal combustion engine in which divided fuel injections are performed in the intake stroke. The divided fuel injections are performed for the purpose of mainly reducing a soot amount (an amount of particulate matter) in the exhaust gases. Specifically, JP'421 describes the controls described below: a control in which the completion timing of the divided fuel injections in the intake stroke is advanced after completion of the warming-up of the engine, a control in which the first injection timing in the intake stroke is advanced as the engine rotational speed increases (FIG. 4 of JP'421), a control in which the number of the divided fuel injections is reduced as the engine rotational speed increases (FIG. 5 of JP'421), a control in which the fuel pressure is increased when the demand fuel amount cannot be injected with a single injection, and the like.
In the engine which is configured so that the tumble flow is generated in the combustion chamber, a fuel adhering state indicating how the injected fuel adheres to the inner wall of the combustion chamber or to the top surface of the piston (upper surface of the piston defining the combustion chamber), changes depending on whether the fuel injection is performed before generation of the tumble flow or after generation of the tumble flow. However, this point is not considered in the direct fuel injection internal combustion engine shown in JP'421.